Materials testing device



March 6, 1956 J. w. T. VAN ERP 2,737,048

MATERIALS TESTING DEVICE Filed Jan. 12, 1953 I 3 Sheets-Sheet 1 IN VEN TOR.

Jo/wv W T. VAN ERP BY g4, wwww nrramve'vs INVENTOR.

3 Sheets-Sheet 3 March 1956 J. w. 'r. VAN ERP MATERIALS TESTING DEVICE Filed Jan. 12, 1953 Jbhw \N. 7? VANERP BY @4,

ATTORNEYS United States Patent-"O MATERIALS TESTING DEVICE John W. T. Van Erp, Cleveland, Ohio Application January 12, 1953, Serial No. 330,615

15 Claims. (Cl. 73-79) This invention relates to improvements; in a materials testing device, and more particularly to one in which a hammer-is caused to. rebound from the. materialbeing tested, and the amount of the rebound is: indicatedby a .pointer.

One of the objects of the present invention is the provision of a hammer assembly mounted in a frame, wherein the hammer assembly is completely balanced to'eliminate the influence of gravity. This permits the instrument to be used in any position, such as vertical, horizontal, or inclined.

Another object of the present invention is-the utilization of strong spring-means for producing the striking action of the hammer against the materialto bestested, the arrangement being such that a very strongspringmeans can be used, thus insuring .thegreatesttdepth: of impact influence when'the hammerstrikesthe: material being tested, without appreciably. exceeding. theuelastic behavior of the tested material.

A further object ofthe present. invention :is to. provide stop means including a trigger for uniformly predetermining the amount of stress of the spring-means. so; that the blow struck by the hammer will, always beuniform.

A further object of the present invention is toprovide catch means interengaged between the hammerpassembly and the pointer or indicator, this connectionrbeinggoperative only upon the rebound movement of the hammer assembly so as to carry the indicator overindi'ciarzindieating the amount of, rebound of the hammer.

A further object of the present invention is toxprovide a lever for cocking the spring andengaging'ihe. hammer assembly with the releasing trigger, which'cockingklever at the. same time, during its cockingmovementrpushes.

the pointer engaging catch into its retractedposition and returns the pointer towardzero ready, for. theznext=readmg.

Other objects and advantages of theqpresentzinvention will be apparent from the accompanying-'1drawingsizand description, and the essential features; thereof. willzrbe set forth in the. appended claims.

In the'drawings,

Fig. 1 is a side elevational viewof aninstrumentembodying my invention.

Fig. 2 is a longitudinally extending, section through the same, taken along the line 2-2 of. Fig. 9 and iwith the hammer assembly moved to cocked-position,

Fig. 3 is an enlarged fragmental view ofythe lower central portion'of Fig.'l with the pointeromittedi so as to more clearly disclose the pointer engaging-match.

Fig. 4 is a fragmental sectional view taken. along the line 4-4 of Fig. 3.

Fig. 5 is a view similar to Fig. 4 illustrating-ghowathe cocking lever moves the catch into its retracted-position.

Fig. 6 is a. fragmental sectional. view takenalong the line 6-6 of Fig. 1.

Fig. 7 is a fragmental view of theapartsgfound in the central portion of Fig. 1, the parts, being. shown .insfla difierent position in Fig. 7

' the framejs')thesmosttnatural place forv one hand .to be .,pl aced,.whilefithe.othelihand holds, the gripportion 15b.

'of;'levers...23,. and a. counter-weight 24. :hasra removable head 22a, made of hard steeh-which is ,heldgtim place by wset screw 22b. pivotallyvmounted at 25- intermediate their ends between ,the1walls'15a, and more particularly between the portions 17 ofztthose .walls; :by thez'frarne. 15, guide the hammer 22 for move- 55 This.= provides the familiarparallel ruler arrangement.

2,737,048 Patented Mar. 6, 1956 ice ;Fig.; 8;-;-is.-:a;.fragmental sectional view taken=along-the line" 88:,Of 1Figrl7.

Fig.9 is a..top. .plan view of the device of Fig. 1.

Fig. .10;is.1a:..transverse: sectional view taken along-line Ill -10 of Fig.9.

Figrll is'a transverse sectional view taken along the linell-ll of Fig. 1.

Fig. l2'is a perspective view of the pointer return pingadjustmentidevicershown in Fig. 8.

, My. de.vice. operates. on a principle similar to that found in known hardness testing devices wherein a weight is; causedxtowrebound from the material being tested, and the amount-of rebound ismeasured. These previously knowndevices-areugenerally usable only in a vertical position wheretherebounding weight is dropped-verticallydownwardly, or they cannot be utilized to test'materialsswhichaarepart of constructions located in the-field, orthey. have-a tendencyto slightly damage the material dur ngtest. My invention overcomes these diificulties vin that'itcanbe utilized in any position, it can be carried .prises two;.spaced-apart-. generally parallel Walls having upper:portionsalfizwhich are more widely spaced and lowerportions:17.:which are less-widely spaced. The grip portion 15b,, asamostclearly shown in Fig. 11, comprises twoggenerally'parallelwalls 18 which are rigidly welded to :thegun-:portion 15. These walls are connected across the reanbya plate19 and across the front by a shorter ;plate,a20. .Thelower-end of the handle grip portion bendsvforwardly and is-secured to a shallow channel ..m ember 21;:theupperend'of whichis welded to the gun portion 15a.

.Thezhammer' assembly comprises the hammer2'2, a pair The hammer The levers 23 are Thelinear pivots 25, supported menti generally in :a plane. The upper'ends of -the leversz23 arewpivotally= connected at 26 to the ham- At their lower ends,-the levers 23 are pivotally connected .aILZTtO thecounterweight 24. The arrangement is such that-the hammenassembly isalmost perfectly balanced 1 aboutlthe pivots-25w that the same rebound occurs in 'I have here'shown'theportions 16 extended upwardly in ears 16a, and a tubular handle 28 is provided rigidly connected to theears 16a andpreferably extending laterally outwardly atone side or at both sides of'the gun portion 15a. Other arrangements of'this handle might be maderbut Ibelievedtheupper forward portion of The means which urges the hammer toward striking position comprises two tension springs 29, which are in tension between a portion of the frame and a portion of the hammer assembly. At their forward ends, the springs pass over a yoke 3%, which is held in the tubular handle 28 by means of a bolt 31. The bolt is threaded through the yoke and this permits adjustment of spring tension within certain limits. The rear ends of the springs 29 are hooked over wings 23a at the upper ends of the levers 23. One position of the springs 29 is shown in full lines in Fig. l. A second position of these springs is indicated in dot-dash lines, where the springs have been carried to the second lever so as to place them under greater tension.

When the hammer assembly has been moved from the striking position of Fig. 1 to the cocked position of Fig. 2, means is provided for holding the hammer assembly in this cocked position. A trigger 32 is pivotally mounted between the walls 17 on a pivot 33. Spacers 34 hold the trigger in proper position centered in the gun portion a. The upper end of the trigger is formed into a hook 32a and the rearmost pivot bolt 26 is adapted to engage behind the hook 32a, as shown in Fig. 2, to hold the hammer assembly in cocked position. Referring to Fig. 9, it will be noted that the hammer 22 is cut away at 35 so that the bolt 26 (or a sleeve thereover) is adapted to engage the hook. A spring 36 biases the trigger counterclockwise about the pivot 33 as viewed in Fig. 2. To release the hammer assembly, the trigger is moved in a clockwise direction by a hand of the operator holding the handle grip portion 15b. The hammer then moves from the position in Fig. 2 to the position of Fig. 1 and strikes a blow against the material to be tested M. It will be noted in Fig. 1 that the hammer 22 in striking position is at right angles to the central axis through the levers 23. Preferably, positioning members 37 and 38 are arranged to properly position the apparatus against the material to be tested. The stop members 37 are at the ends of and supported on the front of the handle 28. The lower stop member 38 is placed near the lower end of the gun portion 13a. These three stop members 37 and 3S define a plane which is the same plane as that struck by the hammerhead 22a in the striking position previously defined. This insures that the hammerhead 22a hits the surface of the test material M on the moment of impact exactly perpendicular so that there is no lateral movement and resulting friction losses of rebound energy.

An indicator or pointer 39 is pivotally mounted at 40 between the walls 17 so as to indicate the rebound of the hammer from the position of Fig. 1 after it has struck the impact blow against the material to be tested. The

pointer 39 is made as light as possible so as to influencev the reading as little as possible. It may be made of a thin plate bent in an L shape and it made he made of aluminum to save weight. Referring to Fig. 1, that portion of the pointer 39 below the line 39a is of such thin sheet metal construction. Above the line 39a, a weight 3912 is secured to the pointer so that the weights on opposite sides of the pivot axis 40 are equally balanced. The pivot 44?, as best seen in Fig. 10, is so constructed as to hold the pointer 39 by friction in any position to which it is moved. The pivot is actually the bolt 40 which passes through the plate 17, there being a brass washer 41 between the pointer and the plate 17. Nuts are provided at opposite ends of the bolt, and on the outside a washer 42 holds a spring 43 between the washer and the pointer 39 so that the pointer is always held by spring pressure against the Washer 41.

Means is provided on the hammer assembly for moving the pointer 39 in its rebound indicating movement only upon movement of the hammer assembly away from the material M upon the rebound after the hammerhead 22a has struck a blow against the material. In the present instance, a catch 44 is mounted in a slot in the counterweight 24 at the lower rear end thereof, as clearly shown in Figs. 1, 3, 4, and 5. The catch is generally triangular in shape and pivots about. the point 45. Referring to Fig. 5, the normal retract position of the catch 44 is there shown. In this position, the catch 44 does not engage the pointer 39. When the hammer 22 is moving toward the right, as viewed in Fig. 1, the counterweight 24 is moving toward the left. As the hammerhead 22a strikes the material being tested, the counterweight 24 suddenly comes to a stop. Referring to Fig. 5, it will be noted that the major portion of the weight of the catch 44 is down and toward the right with respect to the pivot point 45. When the counterweight 24 stops suddenly, the inertia of the catch 44 causes it to swing from the position of Fig. 5 to the extended position of Fig. 4. The catch is held in this extended position by means of the spring 46, which is fastened about pin 47 in the counterweight and has its opposite end secured in a hole 48. The bent end 46a of the spring 46 engages against the edge 44a of the catch and holds it in the extended position shown in Figs. 3 and 4. Referring to Fig. 10, when the catch 44 is in its extended position, it engages a lip 390, which is bent inwardly from the pointer 39. Then when the hammer 22 bounces toward the left, as viewed in Fig. 1, after striking the material M, the counterweight 24 moves toward the right and catch 44 carries the pointer 39 in a counter-clockwise direction from the position shown in Fig. 1. This causes the pointer to travel over the indicia 47 from the zero or starting point toward the indicia 1d at the opposite end. The reading on this scale may then be compared with the chart previously referred to in order to get an indication of the hardness of the material tested. Preferably, the plate 17 on one side of the frame is extended downwardly as indicated at 17a for the purpose of carrying the indicia 47. Preferably, the portion 17a is provided with a stiffening angle-forming member 17b, as shown in Fig. 6 so as to give rigidity to the portion carrying the indicia.

A cocking lever 49 is provided pivotally mounted between the walls 17 at 15. This cocking lever is generally channel form in shape, opening toward the front of the main frame. A short plate 49a ties the flanges of this channel form together at the front side of the lever. As the cocking lever moves in its cocking movement counterclockwise, as viewed in Figs. 1 and 2, in the direction of the arrow A, the plate 49a engages against the catch 44 as seen in Fig. 4. Since the point 44b of application of force from the lever 49 provides a counter-clockwise turning movement for the catch 44 about its pivot 45, as viewed in Fig. 4, the catch will be automatically returned to its retracted position as shown in Fig. 5 upon further movement of the cocking lever 49 in its cocking direction.

Means is provided on the cocking lever for automatically returning the pointer 39 toward its zero on the scale 47. This construction is clearly shown in Fig. 12 and comprises a pin 51 carried in a block 52, which in turn rides in a notch 49b of one of the flanges of the lever 49. An adjusting screw 53 is threaded through the web 49c of the lever 49 and is also threaded through the block 52. Fig. 8 shows how pin 51 engages the pointer 39 on the left hand side of its pivot 40, as viewed in Figs. 1, 7, and 8 so as to cause counter-clockwise movement of the pointer 39 from the position of Fig. 7 to the position of Fig. 1. The plate 17 is cut away as shown at 54 to permit this pointer adjusting movement of the pin 51. The screw 53 may be adjusted by means of its knurled thumbpiece so that the pointer 39 is returned no further than just a little below the expected test readings on the indicia 47. This reduces the amount of energy used in moving the indicator upon taking the next reading, thereby increasing the accuracy of the instrument.

In use, the cocking lever 39 is moved from the brokenline position of Fig. 2 to the full-line position thereof. During the first portion of this cocking movement, as

the lever- 49 is moved from thefull-line position of Fig. l to the broken-line position. there shown, the catch .44 is moved from the position of: Fig. 4 tothe retracted position of Fig.- 5. Further cocking movement of the lever '49 carries the hammer assembly fromv the .position of Fig. 1 to thecocked position of:Fig. 2, where it is held .by the trigger 32. The .final movement of the cocking lever in cocking direction causes the, pin 51 to engage the end-39h of the pointer 39 and return it back toward zero on the indiciav 47. The frame is .then graspedby the hand grip portion 15b and bythe handle 28 and-presentedto thematerial M to be tested. The stopmembers. 37 and 38 are placedagainst this material toobe tested. The trigger 32 is then pulled, releasing-the hammer assembly to the actionof-the springs 29, which causes it tomove rapidly from the position of Fig.;2-tothe position-.of Fig. 1. Upon striking the material to. be tested, thecatch 44 is thrown outwardly to its-extendedposition asshown in;Fig. -;4. Upon, rebound of thehammer-22from the material tested, the counter-weight 24 moves ina counterclockwise direction about th'epivots 25, as'viewed in Fig. 1, andv the catch 44, engaging the li'por ear 39c, carries theqpointer 39 toxa position along ther indicia 47, which is a. true measure;f the rebound of-the: hammerfrom the material tested. Due'to the construction at-the pivot 40, the pointer r'emains in this position.

At 55in Fig. l, I have indicated in long-dashlines the outlines ofa' protective casing which may be placed over themovingparts; This casing may beentirely transparent 'orit may have-awindow over the indicia 47 so that the latter may be easily read;

What I claim is:

l. A materials testing device compris'ing a' frame, a

hammer assembly including,a rigiduhammer and linear pivot means mounting said hammer in said frame for striking movementout of-said. frame and for rebound movement back into saidframe, said 'mean's 'and said frame constraining said hammerwfor. movement generally in a plane,--means counterbalan'cing s'aid hammer about said pivotal connection to said frame, said frame having a face for presentation to material to be tested, means for causing said striking movement of said hammer, and means for indicating the amount of rebound of said hammer following its striking movement.

2. The combination of claim 1 wherein said mounting means is a parallel linkage system.

3. The combination of claim 1 wherein said means for causing said striking movement is spring means urging said hammer out of said frame, and stop means for uniformly predetermining the amount of stress of said spring means.

4. The combination of claim 3 including means for varying the pull of said spring means.

5. The combination of claim 1 wherein said indicating means includes a pointer pivotally mounted on said frame, a catch carried by said hammer assembly and engageable with said pointer only responsive to rebound movement of said hammer, and means for retaining said pointer in any position to which it is moved by said catch.

6. The combination of claim 5 including a cocking lever pivotally mounted in said frame, spring means between said frame and assembly for causing striking movement of said hammer, said cocking lever during cocking movement engaging said assembly and moving the same in spring-means-stressing direction, and a releasable trigger for holding said spring means stressed, and said cocking lever having a portion engaging said pointer during cocking movement of said lever and returning said pointer toward its initial starting point before any indication was made.

7. The combination of claim 6 wherein said pointer engaging portion of said cocking leveris adjustable in a directionto vary the, amount of returnvof said .pointer toward its initial starting point.

8. A.materials.testing device operable by striking a hammer against materialto be tested and comprising a frame having a gun portion at the top and a handle grip portion :extending downwardly from the rear end of the gun portion, said gun portion including two spaced generallyparallel walls, two levers pivoted between said wallsand extending above andbelow said walls, a hammerpivoted to the upper ends of said levers ina parallel linkage arrangement, whereby said hammer and levers andv counterweight provide a. hammer assembly, a counterweight pivoted to the lower ends of said levers, atrigger-pivoted between, saidwalls near the upper end of saidhandle portion, atension spring connected betweenthe upper end of said'hammer assembly and the upper front part of saidgun portion,- a hook on said trigger in positionto engage and hold a part of said hammer assembly when said spring is cocked, a pointer pivotedito oneof said-walls for movement in a plane parallel tosaid hammer. movement, said pointer and counterweight movinginadjacent parallel paths, a catch on said-counterweight normally retracted out of the path of said pointer but: movable by its own inertia into extended pointer *engagingposition upon sudden stoppage of said counterweightupon said hammer striking tested material, indicia carried by said frame near one end of said pointer, and a 1 cocking lever; pivotally mounted .betweensaid walls in front of the upperend of said handle gripportion, said cocking lever engaging said hammer assembly-and carrying. saidassembly to springcocking position.

9. Theacombination of lclaim 8 wherein said cocking lever engages said catch during cocking movement of said-lever and. moves said catchi into retracted position.

10. The-combination of .claim. 8 wherein said cocking lever engages said; pointer. during cocking movement of said'leverand moves said-pointer toward its. initial startingposition.

llLThe combination-of claim 8;inclu'ding a handle at the upper forward part of said gun portion.

12. A materials testing device comprising a frame, a hammer assembly including a hammer and means mounting said hammer in said frame for striking movement out of said frame and for rebound movement back into said frame, said means being pivotally connected to said hammer and to said frame, means counterbalancing said hammer about said pivotal connection to said frame, means for causing said striking movement of said hammer and assembly, means for indicating the amount of rebound of said hammer following its striking movement, said mounting means is a pair of parallel levers, each lever pivoted intermediate its ends in said frame, a pivotal connection between the upper end of each lever and said hammer, the distance between said two pivots on each said lever being the same, said frame having a substantially plane face for presentation to material to be tested, and the axis of said hammer being substantially normal to a line between the two pivots on each lever when the striking face of said hammer lies in said plane.

13. A materials testing device comprising a frame, a hammer assembly including a hammer and means mounting said hammer in said frame for striking movement out of said frame and for rebound movement back into said frame, said means being pivotally connected to said hammer and to said frame, means counterbalancing said hammer about said pivotal connection to said frame, means for causing said striking movement of said hammer and assembly, means for indicating the amount of rebound of said hammer following its striking movement, said mounting means is a pair of parallel levers, each lever pivoted intermediate its ends in said frame, a pivotal connection between the upper end of each lever and said hammer, the distance between said two pivots on each 7 lever being the same, a counterweight pivotally connected between the lower ends of said levers, and the parts connected to opposite ends of said levers being approximately exactly balanced about the pivot connections of said levers within said frame.

14. A materials testing device comprising a frame, a hammer assembly including a hammer and means mounting said hammer in said frame for striking movement out of said frame and for rebound movement back into said frame, said means being pivotally connected to said hammer and to said frame, means counterbalancing said hammer about said pivotal connection to said frame, means for causing said striking movement of said hammer and assembly, means for indicating the amount of rebound of said hammer following its striking movement, said mounting means is a pair of parallel levers, each lever pivoted intermediate its ends in said frame, a pivotal connection between the upper end of each lever and said hammer, the distance between said two pivots on each lever being the same, a counterweight pivotally connected between the lower ends of said levers, and the parts connected to opposite ends of said levers being approximately exactly balanced about the pivot connections of said levers within said frame, said indicating means includes a pointer mounted on said frame for movement in a path close alongside said counterweight, a catch pivotally mounted on said counterweight, said catch having the major portion of its weight on that side of its pivot toward said pointer path whereby stoppage of said counterweight suddenly, upon striking impact of said hammer, causes said catch to be thrown from a retracted position to an extended position, and said catch in retracted position lying outside of said pointer path and in extended position lying in the path of movement of said pointer.

15. A materials testing device comprising a frame, a hammer assembly including a hammer and means mounting said hammer in said frame for striking movement out of said frame and for rebound movement back into said frame, said means being pivotally connected to said hammer and to said frame, means counterbalancing said ham- 8 v me: about said pivotal connection to said frame, means for causing said striking movement of said hammer and assembly, means for indicating the amount of rebound of said hammer following its striking movement, said mounting means is a pair of parallel levers, each lever pivoted intermediate its ends in said frame, a pivotal connection between the upper end of each lever and said hammer, the distance between said two pivots in each lever being the same, a counterweight pivotally connected between the lower ends of said levers, and the parts connected to opposite ends of said levers being approximately exactly balanced about the pivot connections of said levers within said frame, said indicating means includes a pointer mounted on said frame for movement on a path close alongside said counterweight, a catch pivotally mounted on said counterweight, said catch having the major portion of its weight on that side of its pivot toward said pointer path whereby stoppage of said counterweight suddenly, upon striking impact of said hammer, causes said catch to be thrown from a retracted position to an extended position, and said catch in retracted position lying outside of said pointer path and in extended position lying in the path of movement of said pointer, a cocking lever pivotally mounted in said frame, said cocking lever during cocking movement being movable into engagement with said catch in direction to return said catch to retracted position, spring means between said frame and assembly for causing striking movement of said hammer, said cocking lever during cocking movement engaging said assembly and moving the same in spring-meansstressing direction, and a releasable trigger for holding said spring means stressed.

References Cited in the file of this patent UNITED STATES PATENTS 1,586,363 Hall May 25, 1926 1,708,262 Davis Apr. 9, 1929 1,781,615 Von Lessen Nov. 11, 1930 2,207,502 Zamboni July 9, 1940 

